Ian

“The Pusher, Chapter 3, Part 13:

The gunslinger had known magicians, enchanters, and alchemists in his time. Some had been clever charlatans, some stupid fakes in whom only people more stupid than they were themselves could believe (but there had never been a shortage of fools in the world, so even the stupid fakes survived; in fact most actually thrived), and a small few actually able to do those black things of which men whisper—these few could call demons and the dead, could kill with a curse or heal with strange potions. One of these men had been a creature the gunslinger believed to be a demon himself, a creature that pretended to be a man and called itself Flagg. He had seen him only briefly, and that had been near the end, as chaos and the final crash approached his land. Hot on his heels had come two young men who looked desperate and yet grim, men named Dennis and Thomas. These three had crossed only a tiny part of what had been a confused and confusing time in the gunslinger's life, but he would never forget seeing Flagg change a man who had irritated him into a howling dog. He remembered that well enough. Then there had been the man in black.”
― Stephen King, The Drawing of the Three